Recent legislative and regulatory changes require that a local exchange carrier (LEC) unbundle certain network elements and services and offer use of those elements and services to other carriers for resale to end users. In one required implementation the LEC will sell the other carrier an unbundled port on an end office switch and allow the other carrier to become a competing local exchange carrier (CLEC) by reselling services of the switch to end users having local loops which connect to the end office switch. Those statutory and regulatory changes also specify that customized routing is required for both unbundled switching and for resale. Customized routing is the term used in the regulations for routing calls made in the local exchange carrier (LEC) switch to locations other than those that exist today. The primary applications are for unbundlers and resellers to have operator (0+, 0-) calls and directory assistance calls (411/555) routed to their own platforms. Other types of calls could possibly be applicable as well, but the 0+/0-/411 calls are the ones in most immediate demand.
This type of customized routing in an interconnection environment represents a capability that currently does not exist in the network architecture of LECs. The currently used switches in the LEC public switched telephone networks were not designed with this functionality in mind. The capability does not exist and the switches are not readily adaptable to provide customized routing. This applies to all of the predominantly deployed switches (5ESS, 1AESS, EWSD, and DMS-100) from three major switch manufacturers, Lucent Technologies (formerly AT&T), Nortel, and Siemens.
One prospective unbundler and reseller has suggested use of line class codes (LCCs) to accomplish this purpose. However, any implementation of customized routing using LCCs would require use of an excessive number of such codes and would produce other serious problems. Not only is there a limit to the capacity of the switch regarding the number of LCCs that could be physically provisioned, managing the new operational environment is at least as critical. The provisioning and maintenance systems that support the LEC's services cannot be ignored. These systems allow telephone services to be ordered, provisioned, monitored, repaired, and billed; they are an essential element in contributing to the quality of service enjoyed today by the public LEC's customers.
Without incorporating new LCCs into the operations systems that support services, severe problems would have to be expected in provisioning services. Manual provisioning would require human intervention and complex lookups that involve locating the correct code in a table of thousands. Such a process would be prone to both error and delay resulting in service degradation. It is for this reason that today's process is mechanized. In an environment with considerably more codes, a mechanized process would be even more important.
The line class code approach would use existing switch resources in a manner that was never intended. Such an application is untested and to some degree would have unknown consequences if deployed on any meaningful scale. Even the proponent of this approach has indicated that LCCs would be an interim and limited workaround which would need to be reversed once a longer term solution could be developed.
Another proposal for coping with the problem has been the possible use of an Advanced Intelligent Network (AIN) common channel signaling (CCS) solution. However, this is not feasible in view of the fact that, while the AT&T 1AESS switch has AIN capability, it will not apply AIN type processing to 0 calls. In that switch, the 0 number routing functionality takes precedence over all other types of call processing, including AIN processing.
The patent literature suggests various approaches to more or less analogous problems.
U.S. Pat. No. 5,550,912, issued Aug. 27, 1996 to Akinpelu et al., and U.S. Pat. No. 5,475,749, issued Dec. 12, 1995 to Akinpelu et al., assigned to AT&T Corporation, disclose specialized call processing in an interexchange carrier (IXC) network to route calls via a LEC and a CLEC or competing local exchange carrier (termed a `competing access provider` or `CAP` in these patents).
In one aspect of the Akinpelu et al. call processing, the switch of the IXC network serving as the egress point for a call, checks the area code (NPA) and office code (OC or NXX) of the dialed number to determine if `exception` routing is necessary, i.e., to determine if the destination station lies in a region served by a LEC and one or more CLECs. If no exception routing is necessary (LEC only), the egress switch routes the call through the LEC carrier switch in the normal manner. However, if exception routing is necessary, the egress switch checks the last four digits of the called number against an exception table to determine if the particular number is served through a CLEC switch or a LEC switch. The table look up can utilize translation tables in the egress switch or tables in a remote database. If the last four digits from the dialed number are listed in the exception table, then the egress switch routes the call through the CLEC's switch. If the last four digits from the dialed number are not listed in the exception table, then the egress switch routes the call through the LEC's switch. If the called customer receives service from both a CLEC and a LEC, the egress switch will route the call through the CLEC switch unless all trunks between the IXC egress switch and the CLEC switch are busy, in which case the egress switch routes the call via the LEC switch.
The Akinpelu et al. Patents also disclose a specialized translation and routing process at the ingress switch of the IXC network. In some cases, a different egress switch serves a CLEC than serves a LEC. For such a case, the ingress switch queries a database. The database identifies the called customer's preferred local exchange carrier and possibly an alternate carrier. Based on the local carrier identification (LEC or CLEC), the ingress switch routes the call through the appropriate egress switch. Data identifying the IXC egress switch, the preferred and alternate carriers and the identity of the terminating switches of the preferred and alternate carriers are transmitted via CCS messages to the egress switch, to eliminate the need for further translation by the egress switch.
U.S. Pat. No. 5,473,681, issued Dec. 5, 1995 to B. Waring Partridge, III, assigned to AT&T Corporation, relates to processing of telephone calls through two or more carriers. Such calls may involve a local exchange carrier and an interexchange carrier, a wireless carrier and a local carrier, or any combination of multiple local exchange carriers and interexchange carriers. In a mobile telephone call, for example, a wireless carrier may route the call through an interexchange carrier to a distant local exchange carrier to complete the call.
A second carrier is preselected as a default primary interexchange carrier (PIC). However, the caller also may select the second carrier on a per call basis by dialing an interexchange access code.
Partridge, III teaches that, for each call in which a telecommunications carrier code specifying a particular carrier is supplied by a caller, the network of the local service provider routing such a call transmits to the selected IXC carrier network an indication that the carrier code was dialed by the caller. The local service provider network may also transmit an indication, if applicable, that the entered carrier code is not the default carrier code. The local service provider network transmits these indications regarding second carrier selection as SS7 messages or portions thereof. The second or interexchange carrier may use the carrier selection indications, for example, to control provision of certain special services on the respective calls.
U.S. Pat. No. 5,333,184, issued Jul. 26, 1994 to Doherty et al., assigned to AT&T Bell Laboratories, discloses a system for recording the `primary interexchange carrier` identification for the called party. The interexchange carrier typically processes calls from calling parties who have PIC'd that carrier for their long distance services. By recording the PIC of the called party as well, the interexchange carrier can offer special billing treatments for calls from one subscriber to any other one of that carrier's own subscribers.
In the network illustrated in FIG. 1, subscribers 11, 12 obtain local switched telephone service from a local exchange carrier (LEC) network 20. The LEC network 20 includes a number of local switching offices 21, 22. When a subscriber for example at station 11 dials a long distance call, the serving switching office 21 recognizes that the call is a long distance call based on the area code digits. A global PIC database 26 stores PICs for all subscribers serviced through the LEC network 20. In the example, in response to the long distance call from station 11, the switch 21 accesses the global PIC database 26 to identify the primary interexchange carrier selected by or for the particular calling subscriber.
Using the PIC identification from the global database 26, the serving switching office 21 routes the long distance call to the originating switch of the selected interexchange carrier, in the disclosed example, to the originating switch 301 of the interexchange carrier network 30. The interexchange carrier network 30 routes the call to a terminating switch 302.
The called party is served by a LEC network 40, similar to the LEC network 20. In the disclosed example, Doherty et al. assumed that the called party was located at station 51. The terminating interexchange carrier switch 302 therefore routes the call through the switch 41 of the LEC network 40, and the switch 41 completes the call to the station 51.
At call completion, the originating interexchange carrier switch 301 generates an AMA record of the call. A message accumulator system 311 or 312 periodically polls the switches, including the switch 301, to obtain the various AMA records recorded by the switches. Each message accumulator periodically sends the accumulated AMA records to EMI formatting systems 321, 322 for translation into standard "exchange message interface" record format. The EMI formatting systems 321, 322 in turn forward the EMI records to rating systems 331, 332 to compute the toll charges or `rate` each call.
In addition to the normal rating of calls, the rating systems 331, 332 also access one of the interexchange carrier (IXC) PIC databases 351, 352. The databases 351, 352 indicate whether the called party has the PIC'd the same interexchange carrier. For example, the databases may list telephone numbers for all subscribers PIC'd to the carrier 30. If the called party telephone number is present in the database 351 or 352, then the called party is in fact a customer of the carrier 30. The rating systems 331, 332 use the databases 351, 352 to determine if the called party is a customer of the present interexchange carrier and add a called party PIC indicator to the EMI record for the call. The indicator at least signifies whether or not the called party has PIC'd this interexchange carrier.
U.S. Pat. No. 5,311,572, issued May 10, 1994 to Albert Friedes and Om P. Mahajan, assigned to AT&T Bell Laboratories, discloses a system for processing a database-queried call using the call processing capabilities of a carrier's database as well as a subscriber's database. The carrier's database is a routing database. The subscriber's database contains prestored programs and calling party identification related information including background of the caller.
FIG. 1 depicts the architecture of the system. As shown, a station set 105 connects to a Local Exchange Carrier (LEC) telephone network 103 that includes a communication switching system. The LEC network 103 in turn connects to the Action Control Point (ACP) 102 of an Interexchange Carrier's network. The ACP 102 operates as the point of entry for all LEC traffic for switching through the Interexchange Carrier Network 124. The ACP 102 also serves as the access point to a Common Channel Signaling Network for data based queried telephone calls. The carrier's database 106 connects to the STP (Signal Transfer Point) 104 of the Common Channel Signaling Network.
Carrier database 106 is a computer system with mass storage that receives originating information regarding the call from ACP 102 via STP 104. Various carrier switches are also depicted, such as toll switches 110, 111 and 112, and LEC switch 121. These switches are software-driven processor controlled telephone systems designed to route calls either from one switch to another or to subscriber premises equipment, such as PBX 115 and PBX 116. Status Data Network 130 is connected to PBX'S 115 and 116 and subscriber's database 108.
The originating switch forwards origination information, such as ANI, dialed number and caller entered information, through the ACP 102 and the signaling network to the carrier's database 106. The database 106 in turn sends the information to the subscriber's database 108, via the status data network 130. The subscriber's database 108 uses prestored programs and caller related information to formulate a processing label for the call. The processing label includes a routing label to select a destination number for the call and an end point label which includes information to be passed to the subscriber's premise equipment. A billing information label is also provided. The subscriber's database 108 transmits the processing label back to carrier's database 106, and the database 106 returns appropriate instructions to the ACP 102 to control further processing of the call and routing thereof to the subscriber's station equipment.
U.S. Pat. No. 4,565,903, issued Jan. 21, 1986 to Douglas H. Riley, assigned to AT&T Bell Laboratories, relates to call routing in a multi-carrier environment, in particular to the selection of an interexchange carrier and the routing of a call to the selected carrier.
A subscriber is allowed to presubscribe any carrier by having information identifying that carrier entered in a memory associated with the subscriber's terminal link. The subscriber can then have interexchange calls routed to that carrier without taking any additional steps to select or specify the carrier. The subscriber can select any available carrier on a per-call basis by transmitting, e.g., dialing, signals identifying the desired carrier. Thus, a subscriber may prefer one carrier for certain calls and another for other calls. A caller can complete interexchange calls without having to select a carrier by identifying in a second memory a default carrier for calls for which no carrier is specified.
A carrier for an originating terminal link's telephone call is selected by examining dialing signals or the like received over the terminal link to determine whether they include signals identifying a carrier separate from the signals identifying the call destination-identifying. If a carrier cannot be so identified, the contents of a memory associated with the terminal link are examined to determine whether they identify a carrier, typically based on a presubscription to the carrier's services. A second memory can be examined to determine whether they identify a carrier (default) for use when even the memory associated with the terminal link does not identify a carrier. When a carrier cannot be identified, a request is made over the terminal link that a carrier be identified. Once a carrier is identified, the local exchange network attempts to connect the call to that carrier.
U.S. Pat. No. 5,517,562, issued May 14, 1996 to Von K. McConnell, assigned to Independent Telecommunications Network, Inc. of Overland Park, Kans., discloses an intelligent network type system utilizing the networks of independent telephone companies and other telecommunication service providers to offer centralized, custom subscriber services. McConnell provides a centralized network Service Control Point (SCP) and an associated Service Creation Environment (SCE). Individual service providers have service creation terminals of various types, and the SCE terminals are linked to a service creation server. The server also communicates with the network SCE. Participating service providers may each operate a dedicated SCP linked to the network SCP via a high speed data link. Customized services are created via the diverse SCE terminals, and appropriate records are established in one or more of the SCPs to control actual provision of services.
U.S. Pat. No. 5,479,495, issued Dec. 26, 1995 to Mark S. Blumhardt, assigned to U S West Advanced Technologies, Inc., Boulder, Colo., suggests use of an Advanced Intelligent Network (AIN) to automatically access and invoke existing switch-based services, purportedly without requiring the subscriber to take his telephone set off-hook.
As shown in FIG. 1, at least one service node or suitable switch 12 communicates with a plurality of central offices 14 via signaling transfer points (STPs) 15 using the Transaction Capability Application Part (TCAP) protocol. The switch or service node 12 must be operative as the home switch or virtual Service Switching Point (SSP) for subscribers to existing switch-based services. FIG. 1 illustrates the service node 12 as a combination of a Service Control Point (SCP) 16 and a Service Switching Point (SSP) 18. The SSP 18 is the node which actually recognizes the "triggers" used when a subscriber invokes an intelligent network service and then communicates with the SCP to operate the service. The illustrated network is equipped with the O-called-party-busy trigger and leg manipulation functionality of AIN release 1.0.
In operation, the signaling protocol is monitored to detect predetermined triggers and line conditions associated with selected switch-based services. Upon detection of the predetermined triggers and line conditions, a first electrical signal corresponding thereto is generated for receipt by the service node SCP 16. Normal call processing is suspended, and call handling is transferred to the service node. A second electrical signal such as a voice prompt is generated, prompting the subscriber to select the associated switch-based service. If selected, by entry of a DTMF signal or other suitable response, the switch-based service will be automatically invoked. It is not clear how the subscriber hears the prompt and enters the DTMF selection signal without the subscriber's telephone set being off-hook.
U.S. Pat. No. 5,550,911, issued Aug. 27, 1996 to Bhagat et al., assigned to Lucent Technologies Inc., which is the telecommunications equipment company recently spun off from AT&T, discloses call processing techniques for routing calls to an adjunct processor. The adjunct may connect to an originating switch (OSW), or the OSW may access a remote adjunct through a handoff switch (HSW) when the local adjunct is unavailable. The OSW maintains an automatic number identification (ANI) based trigger table. The OSW compares information relating to an incoming telephone call to the customer's trigger table to determine if the call requires processing via an adjunct. If an adjunct is required, the OSW determines the type of adjunct necessary, identifies an adjunct that is capable of processing the call and routes the call to the identified adjunct.
Once the call reaches the adjunct, the OSW or the HSW transfers information to the adjunct, including the ANI information relating to the particular call. The adjunct stores customer specific applications, and processes the call in accord with one such application selected in response to the call related information from the switch.
The adjunct may operate in a query mode to provide information to the switch without interaction with the caller, or the adjunct may interact with the caller using in-band communications. In the query mode, there is no voice connection to the adjunct. The switch is free to route the call upon completion of the query operation. In the interactive mode, the voice call is completed to the adjunct, so that the adjunct may send voice prompt messages and receive DTMF responses. Upon completion of an interactive operation, the adjunct transmits a release instruction to the switch. The release instruction may include a redirection request for transferring the call to an actual destination.